1. Field of the Invention
The present invention relates to a cross-laminated non-woven fabric composed of a warp web and a weft web laminated crosswise together and having a strength in both of the lengthwise direction and the transverse direction. It also relates to a method of making such cross-laminated non-woven fabric.
Throughout the specification and claims, the term "warp web" is used to refer to a web formed of fibers arranged to extend substantially in the lengthwise direction of the web and hence having a larger strength in the lengthwise direction than in the transverse direction. Likewise, the term "weft web" is used to refer to a web formed of fibers arranged to extend substantially in the transverse direction of the web and hence having a larger strength in the transverse direction than in the lengthwise direction. Further, the term "cross-laminated non-woven fabric" is used to refer to a non-woven fabric having a laminated structure composed of the aforesaid warp and weft webs united together into layers with fibers in the warp web extending crosswise with fibers in the weft web.
2. Description of the Prior Art
Conventional random-laid non-woven fabrics are excellent in bulkiness and texture but they have only a limited strength which is not comparable to the strength of woven fabrics. The non-woven fabrics also have excellent water permeability and filtering characteristics. With such excellent water permeability and filtering characteristics, the non-woven fabrics have recently found their new application to "geo-textiles" (fiber materials for the civil engineering and construction). Such new application is however substantially limited due to the limited strength of the conventional random-laid non-woven fabrics. With this difficulty in view, the present inventors have proposed various attempts to increase the strength of the conventional non-woven fabrics. According to one such attempt, there is provided a non-woven fabric having a laminated structure composed of a warp web of parallel-laid non-woven fabric and a weft web of parallel-laid non-woven fabric united with the warp web in such a manner that fibers in the warp web extend crosswise with the fibers in the weft web. The thus laminated non-woven fabric has an increased strength but this strength is still lower than the strength which is necessary for application to the geo-textile for the civil engineering and construction.